The arity (number of accepted arguments) of a handler (method or (({Proc}))
object) is compared to the given arguments submitted by the client for a
RPC ((-Remote Procedure Call-)). A handler is only called if it accepts
the number of arguments, otherwise the search for another handler will go
on. When at the end no handler was found, the
((<default_handler|XMLRPC::BasicServer#set_default_handler>)) will be
called. With this technique it is possible to do overloading by number of
parameters, but only for (({Proc})) handler, because you cannot define two
methods of the same name in the same class.